This is the release number specific to the Arch Linux
release. This allows package maintainers to make updates to
the packages configure flags, for example. A pkgrel of 1
is typically used for each upstream software release and is
incremented for intermediate PKGBUILD updates.

This field specifies the license(s) that apply to the package.
Commonly-used licenses are found in usrsharelicensescommon. If
you see the packages license there, simply reference it in the
license field (e.g. license=(GPL)). If the package provides a
license not found in usrsharelicensescommon, then you should
include the license in the package itself and set
license=(custom) or license=(custom:LicenseName). The license
should be placed in $pkgdirusrsharelicenses$pkgname when
building the package. If multiple licenses are applicable for a
package, list all of them: license=(GPL FDL).

An array of packages that this package depends on to run. Packages
in this list should be surrounded with single quotes and contain at
least the package name. Entries can also include a version
requirement of the form nameversion, where is one of five
comparisons: >= (greater than or equal to), <= (less than or equal
to), = (equal to), > (greater than), or < (less than).

An array of source files required to build the package. Source
files must either reside in the same directory as the PKGBUILD
file, or be a fully-qualified URL that makepkg will use to download
the file. In order to make the PKGBUILD as useful as possible, use
the $pkgname and $pkgver variables if possible when specifying the
download location. Any files that are compressed will automatically
be extracted, unless found in the noextract array listed below.

This array contains an MD5 hash for every source file specified in
the source array (in the same order). makepkg will use this to
verify source file integrity during subsequent builds. To easily
generate md5sums, run makepkg -g >> PKGBUILD. If desired, move
the md5sums line to an appropriate location. NOTE: makepkg
supports multiple integrity algorithms and their corresponding
arrays (i.e. sha1sums for the SHA1 algorithm); however, official
packages use only md5sums for the time being.

Specifies a special install script that is to be included in the package. This
file should reside in the same directory as the PKGBUILD, and will be copied
into the package by makepkg. It does not need to be included in the source
array (e.g. install=pkgname.install).

This array allows you to override some of makepkgs default behavior when
building packages. To set an option, just include the option name in the
options array. To reverse the default behavior, place an ! at the front of
the option. Only specify the options you specifically want to override, the
rest will be taken from makepkg.conf(5). NOTE: force is a special option only
used in a PKGBUILD(5), do not use it unless you know what you are doing.